Material depositing apparatus

ABSTRACT

The invention concerns an apparatus for depositing volatilizable non-thermosetting material on to a substrate. A cylindrical surface is rotated towards and away from the substrate and a feeder head spaced apart from the surface deposits the material thereover. Substantially the whole of the cylindrical surface is heated so that material deposited thereon and moved towards the substrate on rotation of the surface will be vaporized and deposited on the substrate.

I United States Patent 11 1 3,678,888 Davies et al. [4 1 July 25, 1972 [54] MATERIAL DEPOSITING APPARATUS 3,338,738 8/1967 Lindeman ..117/115 x [72] Inventors: Gordon ldris Davies, Kmay Swansea; 3,346,413 10/1967 L1ndeman ...1 17/1 X 3,296,014 1/1967 W1ll1ams ..1 18/50 X Terence Williams, Penllergaer, Glamorgan both of wales 3,406,660 10/1968 S mon ...118/D1G. 23 2,428,868 1/1947 D1mm1ck ..118/49 Assignee: The British Iron and Steel Research 2,391,595 12 1945 Richards et a1. ..l18/49 x sedation, London, England 2,793,609 5/1957 Shen et al. ..1 18/49 22 Filed: Feb. 25 1970 2,925,062 2/1960 Schwindt ..1 18/49 2,403,018 7/1946 Oglesby ..118/48 X [2]] Appl. No.: 13,941

FOREIGN PATENTS OR APPLICATIONS Foreign Application Priority Data 136,247 6/1952 Sweden Feb. 28, 1969 Great Br1ta1n ..10,984/69 Primary Examiner Morris Kaplan 52 us. c1 ..118/48, 219/275 and Brisebfls [51] Int. Cl ..C23c 13/12 58 Field of Search ..1 13/50, 50.1, 48-495; 1571 ABSTRACT 219/2731 275; 1 17/933 The invention concerns an apparatus for depositing volatilizable non-thermosetting material on to a substrate. A cylindrical [56] References cued surface is rotated towards and away from the substrate and a UNITED STATES PATENTS feeder head spaced apart from the surface depositsthe material thereover. Substannally the whole of the cylindrical surface 2,429,862 10/]947 Woofter 8! a1 ..l l8/48 is heated so that material deposited thereon and moved 2,899,528 8/1959 Relcllflll 18/49 X towards the substrate on rotation of the surface will be 3,147,085 l 964 M X vaporized and deposited on the substrate. 3,081,201 3/1963 Koller.... ...118/49 X 3,036,549 5/1962 Iwata et a1. ..1 18/49.1 2 Claims, 7 Drawing Figures Patented July 25,1972 BEST AVAILABLE C 3. .8

4 Shuts-Shut 1 Patented Jul 25, 1972 BEST AVAILABLE COPY 3,678,888

4 Sheets-Sheet 2 Pgtentod July 25, 1912- m AVAILABLE coPY 3,678,888

4 Shuts-Shoot 3 w n% n u ml 1 Patented July 25,1912 AVAHABLE Copy 8.818888 4 Shoo ts-Shdet 4 LLl/ F/QS.

The present invention relates to an apparatus for depositing volatilizable non-thermosetting material, for example epoxy, phenolic (of the Novolak type), or silicone resins or natural oils, etc. on to a substrate, for example moving steel strip.

According to one aspect of the present invention there is provided an apparatus for depositing volatilizable non-thermosetting material on a substrate comprising: a cylindrical surface; means for rotating the cylindrical surface so that a portion of its travel is adjacent a part of the substrate; feeding means spaced apart from the cylindrical surface for depositing said material thereover when the cylindrical surface is spaced apart from its position of nearest approach to the substrate;

and means for heating substantially the whole of the cylindri- I cal surface so that as the cylindrical surface is rotated towards said position of nearest approach the material deposited thereon is vaporized and deposited on the substrate.

If the material deposited on the substrate is radiation curable, the deposited material at the surface of the substrate may be subjected to ionizing radiation, under vacuum, to polymerize the material in the film or coating on the substrate.

The present invention will be more readily understood from the following description, given by way of example only, reference being made to the accompanying drawings in which:

FIG. I is a schematic view of an embodiment of the inventron;

FIGS. 2 and 3 are detailed end and front elevation views respectively of the embodiment of FIG. 1;

FIG. 4 is a part sectional schematic view of a moving strip coating line employing the embodiment of FIG. 1, and

FIGS. 5 to 7 are somewhat schematic views each showing a modification of the embodiment of FIG. I.

The apparatus of the invention will be described with references to depositing epoxy resin on moving steel strip. Turning to FIG. 1, the apparatus there shown comprises a high polish hard-chrome roll 10 mounted for rotation in the clockwise direction as indicated. A reservoir I1 contains the epoxy resin which is to be deposited as a coating on to a moving strip 12 by way of the roll I0. The strip 12 moves in a direction perpendicular to the axis about which the roll 10 rotates. The reservoir is preferably kept at a temperature of the order of 50 to 150 C to keep the resin in a molten state. A positive displacement pump 13 (for example a gear pump) pumps the resin, at the required rate, from the reservoir 11 through a feeder head 14 arranged to deposit the resin on to the roll 10. At the location of the feeder head 14 is an adjustable scraper blade 9.

The roll 10 carries heater elements which heat the surface of the roll on which the resin is deposited. When the heated roll 10 is rotated, a film of epoxy resin is formed on the roll surface. The thickness of this film is determined by the gap between the scraper blade 9 the roll 10, the rotational speed of the roll 10, the pump rate of the pump 13 and the viscosity of the hot resin. By controlling the surface temperature of the heated roll, the liquid epoxy resin can be made to evaporate (or boil" off) and condense on to the strip 12 giving a thin coating of the desired thickness. The surface temperature of the roll will probably be in the range of 150 to 300 C or higher. The evaporated resin is referenced 15 in FIG. I.

The deposition of the resin on the roll 10 and the evaporation and condensation of the resin on to the strip I2 may take place in a vacuum chamber 16. The chamber I6 may be at a vacuum of 0.1 atmospheres or lower. At the entrance and exit locations of the strip 12 into and out of the chamber 16 there would be seals (shown in FIG. 4 at 43 and 44) to maintain the desired level of vacuum within the chamber 16.

The ducting connecting the pump 13 to the feeder head I4 may include pre-set regulating valves 17. A by-pass duct 18incorporating a by-pass valve 20 may be provided.

A de-gas pump 21 connected to the reservoir 11 by way of valve 22 may be employed to remove gas from above the surface of the resin in the reservoir.

Turning now to FIGS. 2 to 4, partsalready described with reference to FIG. I will be given the same reference numerals in FIGS. 2 to 4 as they have been given in FIG. I.

The roll 10 comprises a cylinder 23closed at its ends by plates 24. The roll is fast with stub shafts 25. Rotation of the roll 10 is effected by means of a power source not shown. The shafts 25 are received in bearing housings mounted on upstanding supports; one of these supports is shown at 26 in FIG. 2.

A number of pyrotenax electric heaters is arranged in circu- Iar array around the rotational axis of the roll 10 and the heaters are secured to the end plates 24 of the roll 10 as at 27. Some of these heaters are referenced 28. Electric current is fed to and away from the heaters by way of slip ring collectors 30. Wall portions of the chamber 16 are shown at 31 in FIG. 3.

The feeder head 14 has an adjustable width machined slit 32 from which the epoxy resin will be discharged. The width of the feeder head slit can be adjusted by orthodox methods, e. g. screw adjustment or cam-operated adjusting system. The gap 33 between the feeder head and the roll 10 is made adjustable by reason of the feeder head being carried on an adjustable height mounting 34. The feeder head has electric heaters 35, for example pyrotenax heaters, for maintaining the epoxy resin in a molten state.

The ducting connecting the pump 13 to the feeder head 14 comprises a conduit 36 leading to a pipe manifold 37. Pipes 38 take the resin from the manifold 37 into the feeder head 14. Ducts 40 in the feeder head direct the resin to the slit 32.

In FIG. 2, the film of resin deposited on the roll 10 is shown at 41, and the resin layer deposited on the strip 12 at 42.

FIG. 4 shows (schematically) how depositing apparatus according to the invention could be used in a high speed epoxy resin coating or lacquen'ng plant. Again, items already described have been given the reference numerals previously attributed to them. The moving strip 12 enters the vacuum chamber 16 by way of seal 43 and leaves this chamber by way of seal 44. The strip with the coating of epoxy resin thereon (which resin is radiation-curable) is then cured in the manner disclosed in our British Patent specification No. 1,168,641. The strip enters (and leaves) a vacuum curing irradiation chamber 45 by way of seal 46; within the chamber 45 the epoxy resin coating at the surface of the strip 12 is subjected to ionizing radiation 47 from electron guns 48. Although two guns 48 are shown, there will be only one gun operating to cure the coating that gun being on the same side of the strip as the coating. The ionizing radiation 47 cures the coating by polymerizing the resin in the coating. The level of vacuum in the chamber 45 may be the same as that quoted in the said specification No. 1,168,641 for the chamber 11.

The strip is turned in the chamber 45 by means of guide rollers 50. A guide roller 51 turns the strip after exit thereof from sea] 46. Seals 43, 44 and 46 may be of known design.

In modified forms of the invention, the heated roll 10 is shrouded with baffles or shields defining a space therebetween opening towards the strip 12. Such an arrangement ensures that the evaporated resin is directed towards the strip 12 and thus losses due to vaporization from the roll where it is not adjacent the strip are minimised.

Such a modified form is shown in FIG. 5 wherein the roll 10 is shrouded with deflector shields 52 for directing stray epoxy resin vapor towards the strip 12. The shields 52 have gutters 53 for trapping liquid epoxy resin not evaporated on to the strip 12. The shields 52 are preferably provided with heaters, (four referenced 54), to keep the shields at the same temperature as the roll surface from which evaporation of the resin takes place. The heaters 54 may be pyrotenax heaters.

FIG. 6 shows an alternative design for the shields 52 which, again, are preferably heated to the same temperature as said roll surface. As an alternative to being arcuate as seen in FIG. 6, each shield may comprise two parts disposed at approximately to each other so that the resulting four shields form a generally rectangular outline when seen in end view.

Whereas the embodiments previously discussed can be regarded as direct roller coating embodiments, the embodiment shown in FIG. 7 can be regarded as an off-set roller coating embodiment. Resin from the head 14 is deposited on the roll 10 and from there is deposited on a roll 10 which is in driving engagement with the roll 10 so that rotation of roll 10 will ,7 cause rotation of roll 10. The resin layer on the roll 10' evaporates on to the strip 12. The temperature of the resin receiving surface of the roll 10 will be adjusted so that the resin thereon will be maintained in the molten state but below the vaporization state. 10' is the evaporator roll and the resin receiving surface thereof is heated, for example by pyrotenax heaters, to a temperature at which the liquid epoxy resin thereon will evaporate (or boil" off) and condense on to the strip 12. Shields 52 in the FIG. 7 embodiment serve the same purpose as the shields 52 in the embodiments of FIGS. 5 and 6 and are preferably heated.

Advantages of the FIG. 7 embodiment over the other embodiments are that the epoxy resin coating on the roll 10' of FIG. 7 should be thinner and more uniform than the coatings on the rolls 10 of the other embodiments, and a more uniform coating on the strip 12 will result.

Of course, like reference numerals in all of FIGS. 1 to 7 indicate like parts.

The alternative forms of depositing apparatus shown in FIGS. 5 to 7 may replace the particular form of such apparatus shown in the coating or lacquering plant of FIG. 4.

This invention may be used to deposit non-thermosetting material other than epoxy resin or lacquer on to a substrate which may be stationary instead of moving the depositing apparatus then being mounted for movement relative to the substrate. The said substrate may be strip other than steel strip. The said substrate may not be metal strip. The said substrate may not be strip. The said substrate may be wire for example. The apparatus of the invention is however particularly suitable for moving strip or web.

Preferably, the roll 10 and when used roll 10' rotate continuously in the direction indicated so that the material to be deposited on the substrate is continuously deposited on to the roll 10, 10 from the feeder head 14 or from the roll 10 and continuously evaporates (or boils" off) and condenses on to the substrate.

We claim:

1. An apparatus for depositing volatilizable nonthermosetting organic material on a substrate comprising;

a cylindrical surface;

means for rotating the cylindrical surface about its axis so that a portion of its travel is adjacent a part of the substrate;

feeding means spaced apart from the cylindrical surface for depositing said material on said cylindrical surface and means for spreading said material in a film of predetermined thickness over said cylindrical surface when said surface is spaced apart from its position of nearest approach to the substrate;

a plurality of heaters arranged in a circular array about the axis of, and radially inwardly of the cylindrical surface for simultaneously heating substantially the whole of said surface so that as the cylindrical surface is rotated towards said position of nearest approach the material deposited thereon is vaporized and deposited on the substrate; and shroud means comprising heated baffles defining a space therebetween opening towards the substrate whereby vaporized material deposited on the surface is directed towards the substrate and including gutter means therewith whereby material deposited on said baffles may be received.

2. An apparatus according to claim 1 including means for subjecting said material when deposited on the substrate to ionizing radiation to cure said material. 

1. An apparatus for depositing volatilizable non-thermosetting organic material on a substrate comprising; a cylindrical surface; means for rotating the cylindrical surface about its axis so that a portion of its travel is adjacent a part of the substrate; feeding means spaced apart from the cylindrical surface for depositing said material on said cylindrical surface and means for spreading said material in a film of predetermined thickness over said cylindrical surface when said surface is spaced apart from its position of nearest approach to the substrate; a plurality of heaters arranged in a circular array about the axis of, and radially inwardly of the cylindrical surface for simultaneously heating substantially the whole of said surface so that as the cylindrical surface is rotated towards said position of nearest approach the material deposited thereon is vaporized and deposited on the substrate; and shroud means comprising heated baffles defining a space therebetween opening towards the substrate whereby vaporized material deposited on the surface is directed towards the substrate and including gutter means therewith whereby material deposited on said baffles may be received.
 2. An apparatus according to claim 1 including means for subjecting said material when deposited on the substrate to ionizing radiation to cure said material. 